• The Roadster Factory Recovery Fund - Friends, as you may have heard, The Roadster Factory, a respected British Car Parts business in PA, suffered a total loss in a fire on Christmas Day. Read about it, discuss or ask questions >> HERE. The Triumph Register of America is sponsoring a fund raiser to help TRF get back on their feet. If you can help, vist >> their GoFundMe page.
  • Hey there Guest!
    If you enjoy BCF and find our forum a useful resource, if you appreciate not having ads pop up all over the place and you want to ensure we can stay online - Please consider supporting with an "optional" low-cost annual subscription.
    **Upgrade Now**
    (PS: Subscribers don't see this UGLY banner)
Tips
Tips

Converted to Negative Ground - Battery charging?

Share this page

B

BrandonBJ8

Jedi Trainee
Offline
I just finished the conversion to negative ground. The car seems to be running fine with it. The tach is working which is the part I was worried about most. There are two problems though:

1. I don't think the generator is charging the battery. I tested to battery with a multi-meter and got a reading of 12.05 with the engine running. I revved it up quite a bit and the reading did not change at all.

2. Small, but may be related. The red ignition light comes on when I turn the car on, but does not go off when I get above 1000rpms. It does turn off when I turn the car off though.

Any help or advice would be appreciated.

Thanks!
-Brandon
 
J

Jose_Miguel_Mahave

Freshman Member
Offline
oops, it seems very dangerous to me. I believe you are discharging your battery completely. It happened to me when I reversed the polarity of my bj8


this happens for incorrect conections on the tachometer. It discharges thru the red light
 
J

Jose_Miguel_Mahave

Freshman Member
Offline
i remember there are two small spades that connect the bulb holder with the tachometer chassis. I think they have to be removed to avoid the short circuit
 
Keoke

Keoke

Great Pumpkin
Country flag
Offline
Jose_Miguel_Mahave said:
I would discconect the tachometer while you discover what is going on
Click to expand...


Hold on there the Lot of you! Brandon!, do not start the car again until you have polarised the generator. The generator is polarised for the previous ground configuration and must be redone as part of this conversion. Be back in just abit---Keoke
 
GregW

GregW

Yoda
Platinum
Country flag
Offline
Hi Brandon,
Did you polarize the generator? Go HERE and look at #2 to see how to do it if you haven’t. I’d browse the entire tech article to see if anything was missed. The tach light normally has the same polarity to both sides of the light bulb, one lead from hot battery, the other from the generator. The light comes on at low RPM (or engine off) because it is reading the difference in voltage. Once the RPMs go up and the generator is charging, the voltages become the same (-12 originally) and the light goes out.
 
Keoke

Keoke

Great Pumpkin
Country flag
Offline
T0 Repolarise the generator. Remove both leads from it. Connect a jumper lead from a +12Volt source under the bonnet and momentarily strike it to the small insulated terminal on the generator marked "F" for Field. Reconnect the generator leads and you can now start the engine and you may be good to go. Somtimes reversing the polarity causes the contacts inside the RB340 Controller -Voltage regulator- to burn. But lets see how you get on.--Fwiw--Keoke
 
OP
B

BrandonBJ8

Jedi Trainee
Offline
I polarized it earlier using that exact link above. However, I did not disconnect both leads. Could that be the problem? I just disconnected the smaller terminal and used a live wire from the "B" terminal of the voltage regulator to polarize it (sparked a few times).

Thanks!
-Brandon
 
Keoke

Keoke

Great Pumpkin
Country flag
Offline
No,just so the field is reversed. Does it charge now??--Keoke
 
OP
B

BrandonBJ8

Jedi Trainee
Offline
Re: Converted to Negative Ground - Battery chargin

Keoke said:
No,just so the field is reversed. Does it charge now??--Keoke
Click to expand...

In my previous post I meant that when I did the entire conversion I used that link and am still having the problems. I haven't changed or done anything different since then. Is there something else I can try?

Thanks!
-Brandon
 
Ed_K

Ed_K

Jedi Knight
Offline
Re: Converted to Negative Ground - Battery chargin

Brandon,

You might try to flash the field again.

The indications that you have are that the generator is not putting out anything so assuming that everything else is OK, try flashing it again. You will see a " healthy " spark when you do this. If you did see a fairly noticeable spark when you first flashed it, it may just need to be done again. Give it a try. But when you test it, it should put out 13.5 to 15 volts if it is charging and the red light will go out after it gets above 500- 800 RPMs. If not, turn it off in case something is wrong inside the voltage regulator or the tach is shorting the output from the genrator.

Ed
 
Ed_K

Ed_K

Jedi Knight
Offline
Re: Converted to Negative Ground - Battery chargin

When I converted mine, I got so wrapped up with the tach changes that I almost forgot to swap the polarity of the ground at the battery.
Double check all of the steps that you did if reflashing doesn't help.
 
Keoke

Keoke

Great Pumpkin
Country flag
Offline
Re: Converted to Negative Ground - Battery chargin

BrandonBJ8 said:
Keoke said:
No,just so the field is reversed. Does it charge now??--Keoke
Click to expand...

In my previous post I meant that when I did the entire conversion I used that link and am still having the problems. I haven't changed or done anything different since then. Is there something else I can try?

Thanks!
-Brandon
Click to expand...
Well we better take a look at the voltage regulator. Shut Battery power down on the car. Remove the voltage regulator cover where you will see a very hefty set of points Located on the RH outboard side of the regulator . Using a fine grained non shedding sand paper clean these points and see if charging is restored.---Keoke
 
Dave Russell

Dave Russell

Yoda - R.I.P
Gold
Offline
Re: Converted to Negative Ground - Battery chargin

If you didn't flash the field correctly, the RH contact may be severely burned or missing.
D
 
OP
B

BrandonBJ8

Jedi Trainee
Offline
Re: Converted to Negative Ground - Battery chargin

Okay, now don't get too mad...but I forgot to reconnect the generator after I finished!!! I went back to go a reflash it and saw that it wasn't even connected!

Now the light goes off after about 500rpms and the battery is charging when I rev the engine. It looks like everything is successfully converted and working!

Thanks to all for your help!
 
Keoke

Keoke

Great Pumpkin
Country flag
Offline
Re: Converted to Negative Ground - Battery chargin

BrandonBJ8 said:
Okay, now don't get too mad...but I forgot to reconnect the generator after I finished!!! I went back to go a reflash it and saw that it wasn't even connected!

Now the light goes off after about 500rpms and the battery is charging when I rev the engine. It looks like everything is successfully converted and working!

Thanks to all for your help!
Click to expand...



-------12345678910^?/>,"":&*&**(*&^&*(*&6)__++!@#@!@--Keoke- /bcforum/images/%%GRAEMLIN_URL%%/lol.gif

<span style='font-size: 20pt'> </span> Finese
 
C

Cutlass

Jedi Warrior
Offline
Re: Converted to Negative Ground - Battery chargin

That's ok. Now we've all got lots of troubleshooting advice when it happens to someone else.
 
Similar threads
Thread starter Title Forum Replies Date
Lukens TR2/3/3A Converted TR3A to negative ground. Triumph 0
V MGB Never occurred to me that my '66 would be positive ground. Does the presence of an alternator show that it's been converted? MG 22
donbmw TR2/3/3A Converted to alternator Triumph 14
regularman Have you converted to a forward tilt bonnet? Spridgets 32
1 07 Triumph Daytona 675 converted to Street Triple British Motorbikes 5
J Has anyone converted to TBI? Triumph 11
drooartz Could it be converted to a Sprite carrier? Spridgets 2
R6MGS I've been converted! Triumph 5
S Wedge Anyone Ever Converted a FI TR7 to Carbs? Triumph 5
3 Anyone converted a PI manifold to Motronic? Triumph 6
78Z Hillman Imp converted to Van Other British Cars 9
A Internal hinge converted to external? British Motor Corp 4
P Positive to Negative Conversion Austin Healey 1
S Positive Ground to Negative Ground Power Inverter Austin Healey 11
M BJ8 Positive-Negative Ground Conversion Austin Healey 7
doc50 Nash Metro Positive to Negative Ground Other British Cars 2
G TR4/4A Negative Ground Conversion Question Triumph 11
M TR2/3/3A Positive or negative ground? Triumph 6
P Bugeye Negative Ground Spridgets 15
S MGA 1956 MGA negative ground, True Spark Ignition distributor MG 3
Jim_Gruber Am I set up as Positive or Negative Ground? Spridgets 12
M Negative ground conversion : what about OD ? Austin Healey 9
M Question about positive vs negative ground Spridgets 13
K TR2/3/3A Converting to Negative Ground....... Triumph 12
L The Ultimate Negative Ground Conversion Thread Austin Healey 2
J How can I tell if I have a negative ground tach? Austin Healey 5
M_Pied_Lourd TR2/3/3A Identifying positive or negative ground.... Triumph 14
maxwedge5281 changeover to negative ground in my bn6 Austin Healey 9
A How install a radio with negative mass Austin Healey 3
Marvin Gruber MGA Negative grd- fuel gauge question MG 18
T TR2/3/3A LED tail lights for TR3A and positive vs. negative ground Triumph 11
P TR4/4A Positive/Negative Earth Dilemma TR4A Triumph 11
C Positive or Negative Earth Triumph 15
E Positive ground or Negative ground. What have you? Austin Healey 12
TulsaFred Negative Ground Conversion- inconsistent guidance Spridgets 13
S positive and negative ground Triumph 7
T TR4/4A TR4a positive earth to negative cut over? Triumph 9
memphis Positive to Negative Conversion Austin Healey 2
R Negative Camber 78 Eclat Lotus 8
I Negative grounding questions Spridgets 12
AUSMHLY Is there a negative wire on the directionals? Austin Healey 30
I Bugeye-better to have negative or positive ground? Spridgets 17
I Bugeye negative ground picture? Spridgets 3
J Specific battery for a negative ground? Triumph 4
T TR4/4A TR4a positive or negative earth? Triumph 17
R Fuel gauge / Negative ground Spridgets 9
newmexTR3 positive/negative ground coil question Triumph 14
Newkie Converting Positive ground to Negative ground MG 4
T TR2/3/3A Convert TR3 to negative earth or leave it be? Triumph 14
Magyar How to convert from positive to negative ground? Spridgets 10

Similar threads

Top